A surfboard fin with flexible edges is disclosed in U.S. Pat. No. 5,273,472 (the disclosure of which is hereby incorporated by reference herein) has developed a reputation for being an outstanding product for enhancing safety and control of surfboards, and also has applicability to other watersport boards such as wake boards, windsurfing boards, body boards, water skis, and the like. However there have been some practical problems associated with the construction of the boards. In the practical implementation of the products, a thin ridge (on the order of about 500ths of a centimeter) has been provided extending outwardly from the leading and trailing edges, with rectangular shaped holes provided in the ridge so that the flexible material (typically urethane) extends through the openings during molding, and provides a conventional mechanical lock of the urethane to the rigid body element of the fin. However with this thin ridge construction, it has been difficult to mold the ridge effectively with the holes in it necessary for the mechanical lock, and it is difficult to mold the urethane along the sides of the ridge. Also, when the fins hit a hard object, such as during surfing, such as a reef or a rock, the thin ridge tends to shatter, causing the urethane to separate from the rest of the fin. However if the ridge is made too thick, then the urethane will not have sufficient thickness itself to effectively perform its safety and rudder functions, or a mechanical lock cannot effectively be provided.
According to the present invention a watersport fin is provided which has enhanced functionality both in use and in ease of construction compared to the heretofore commercial versions of the 5,273,472 patent. In the fin according to the present invention, the rigid ridge integral with the rigid body has an average thickness approximately 18-25% of the average thickness of the body element (compared with about 10% in the commercial art), which for most fins translates into an average thickness of about 0.08-0.13 centimeters (e.g. about 0.1 centimeter). According to the invention it is also desirable to have the ridge and the flexible material covering the ridge extend along substantially the entire extent of the rigid body element forming the fin, including the base, thereby enhancing the safety and rudder actions of the fin compared to if the flexible material did not extend along the base.
According to one aspect of the present invention a watersport board fin is provided comprising the following components: A rigid body element having a leading edge and a trailing edge, and an average thickness. A rigid ridge integral with the rigid body and extending outwardly from the leading and trailing edges, the ridge having an average thickness approximately 16-25% of the average thickness of the body element. A plurality of through-extending holes formed in the ridge outwardly of the rigid body element. And, a flexible material covering which substantially completely covers the ridge of the rigid body element along the leading and trailing edges, and extends through the holes formed in the ridge to mechanically lock the flexible material to the ridge, the flexible material being soft enough to minimize injury to a person impacted by a leading or trailing edge of the fin, and being flexible enough to be deflected during movement through water to provide a rudder, anti-cavitation, action.
The flexible material preferably extends outwardly from the trailing edge ridge an average distance greater than it extends outwardly from the leading edge ridge. The rigid body element comprises the base and a tip, the base having a length much greater than the tip (e.g. as is conventional per se a length of over 9 centimeters at the base compared a length near the tip of only about 5 centimeters), and preferably the ridge and the flexible material covering the ridge extend along substantially the entire extent of the rigid body element, including the base, thereby enhancing the rudder action of the fin compared to if the flexible material did not extend along the base. The rigid body element has side faces and the flexible material covers substantially only the ridge, not the side faces, in the preferred embodiment. Desirably the side faces have an uneven contour at the ridge so that the ridge extends outwardly from the rigid body element widely varying distances along the extent thereof which provides more secure attachment of the flexible material to the ridge. The ridge extends outwardly from the rigid body element along the trailing edge an average distance greater than (e.g. at least 10% greater than) it extends outwardly from the leading edge.
In the preferred embodiment the ridge has an average thickness of between about 0.1-0.14 centimeters, e.g. about 0.12 centimeter. While the base of the rigid body element has a width much greater than that of the tip (e.g. about 1.0 cm, tapering gradually to a thickness at the tip of about 0.5 centimeters), the ridge preferably has substantially a constant thickness.
As disclosed in the 5,273,472 patent, the rigid body element may have a Shore D hardness of at least 60 (e.g. at least 78), and the flexible material comprises an elastomeric material with a Shore A hardness of about 40-100. The flexible material preferably is urethane. The flexible material extends outwardly from the rigid body element along the trailing edge an average distance of at least about 0.35 centimeters, which distance is greater than the distance it extends outwardly from the rigid body element along the leading edge.
The side faces of the rigid body element may have an uneven contour at the ridge so that the ridge extends outwardly from the rigid body element widely varying distances along the extent thereof. The average variation of these distances at the ridge extends outwardly from the rigid body element is greater along the trailing edge than the leading edge. As shown in the 5,273,472 patent, preferably the tip is rounded at an intersection between the leading and trailing edges, and both the leading and trailing edges are curved, the leading edge curved toward the trailing edge.
The fin is provided in combination with a watersport board having a top and bottom surface, a front and a rear, the fin mounted on the board bottom surface closer to the rear than the front. The average position of the fin leading edge is closer to the front than the average position of the fin trailing edge. The fin may be glassed onto the board directly in a new construction (such as for example seen in U.S. Pat. No. 5,306,188), or may be part of a removable system, having surface manifestations which allow readily removable mounting to the board.
According to another aspect of the present invention a watersport board fin is provided comprising the following components: A rigid body element having a leading edge and a trailing edge, and an average thickness, and a base and a tip, the base having a width much greater than the tip. A rigid ridge integral with the rigid body and extending outwardly from the leading and trailing edges. A plurality of through-extending holes formed in the ridge outwardly of the rigid body element. A flexible material covering which substantially completely covers the ridge of the rigid body element along the leading and trailing edges, and extends through the holes formed in the ridge to mechanically lock the flexible material to the ridge, the flexible material being soft enough to minimize injury to a person impacted by a leading or trailing edge of the fin, and being flexible enough to be deflected during movement through water to provide a rudder, anti-cavitation, action. And, wherein the ridge and the flexible material covering the ridge extends along substantially the entire extent of the rigid body element, including the base, thereby enhancing the safety and rudder performance of the fin compared to if the flexible material did not extend along the base. The details of the components are preferably as described in the preferred embodiments above.
It is the primary object of the present invention to provide a watersport board fin that is easier to mold--both the fin itself and the flexible material along the leading and trailing edges thereof--than conventional fins of similar design, while at the same time improving the safety and rudder performances of the fin, and providing a more durable arrangement for the flexible material (such as urethane), while at the same time enhancing the flexibility and softness of the urethane. This and other objects of the invention will become clear from an inspection of the detailed description of the invention and from the appended claims.